1. Field of the Invention
The present invention relates to a fault monitoring system and a fault reporting method in which the state of fault occurrence or fault release in transmission systems of various types is detected and reported to a monitoring unit including maintenance personnel, a monitoring device, etc.
2. Description of the Prior Art
In a transmission system that connects multiple transmission devices via transmission paths, a configuration is adopted in which fault occurrence information and fault release information is collected by a monitoring device, either for each transmission device or for the system as a whole, and is reported to the maintenance personnel. In transmission systems of redundant configuration, configurations are also known in which the occurrence of a fault causes a switchover from the in-use side (work side) to the spare side (protection side), and transmission continues using an intact transmission device or transmission path.
Fault occurrence information in a transmission system is information on various abnormal states that are detected, such as a reception signal cutoff in a transmission device, clock signal cutoff, missynchronization, increase in the error rate, or an abnormal temperature increase, and in the case of an unstable operation state, sometimes fault occurrence information and fault release information occur repeatedly in alternation. When an alarm is sent for such a situation, sometimes the alarm is sent and stopped repeatedly. Therefore a device is adopted in which an alarm is sent if the fault occurrence continues for a prescribed time or longer, and the alarm is stopped if the fault release continues for a prescribed time or longer.
FIG. 9 is an explanatory diagram of a conventional configuration and shows an overview of a fault monitoring system, in which 51 is a fault detection unit, 52 is an up-down counter, and 53 is software. Fault detection unit 51 has the function of detecting faults in the units of the transmission devices and transmission system. The detection unit 51 for example outputs xe2x80x9c1xe2x80x9d when it detects a fault occurrence and xe2x80x9c0xe2x80x9d when it detects a fault release; up-down counter 52 increments the prescribed number by a xe2x80x9c1xe2x80x9d fault occurrence detection signal from fault detection unit 51 and decrements the prescribed number by a xe2x80x9c0xe2x80x9d fault release detection signal from fault detection unit 51.
If, by being incremented, the count value of the up-down counter 52 exceeds a preset value, it shows that fault occurrence detection has continued for the prescribed time, so a fault occurrence is reported to software 53. In this way, software 53 immediately reports the fault occurrence to a monitoring unit that includes maintenance personnel or a monitoring device (not shown). If, by being decremented, the count value of up-down counter 52 falls below a preset value, it shows that fault release detection has continued for the prescribed time, so a fault release is reported to software 53. In this way, software 53 reports the fault release to a monitoring unit that includes maintenance personnel, a monitoring device, etc. In this case it is possible to independently set the count value of up-down counter 52, the threshold value for concluding that a fault has occurred, and the threshold value for concluding that a fault has been released.
FIG. 10 is an explanatory diagram of another conventional configuration wherein 61 is a fault detection unit, 62 is a logic unit, and 63 is a software counter unit. The configuration shown in FIG. 9 above is the case in which a hardware counter is used, but the case shown in FIG. 10 is the case in which a software counter is used. Similar to the above-mentioned fault detection unit 51, fault detection unit 61 outputs, for example, xe2x80x9c1xe2x80x9d when it detects a fault occurrence and xe2x80x9c0xe2x80x9d when it detects a fault release.
Logic unit 62 reads the detection signal from fault detection unit 61 in accordance with the reading timing signal of the software, and if this detection signal indicates the fault occurrence detection state of xe2x80x9c1xe2x80x9d, inputs fault detection information to software counter unit 63 as xe2x80x9c1xe2x80x9d and fault release information to it as xe2x80x9c0xe2x80x9d, and if the detection signal from fault detection unit 61 indicates fault release by xe2x80x9c0xe2x80x9d, inputs fault detection information to software counter unit 63 as xe2x80x9c0xe2x80x9d and fault release information to it as xe2x80x9c1xe2x80x9d.
Moreover, logic unit 62 inputs both fault detection information and fault release information to software counter unit 63 as xe2x80x9c1xe2x80x9d if, by the next reading timing signal, the detection signal is different from the previous time it read a detection signal from fault detection unit 61. This software counter unit 63, which has the functions of fault detection state continuation counter and fault release state continuation counter, resets everything to zero if both the fault detection information and the fault release information are xe2x80x9c1xe2x80x9d, and if the fault release information is xe2x80x9c0xe2x80x9d and the fault detection information is xe2x80x9c1xe2x80x9d, it increments the fault detection state continuation counter, and if the count value exceeds the set value, reports a fault occurrence to the monitoring unit of maintenance personnel, monitoring device, etc.
If the fault release information is xe2x80x9c1xe2x80x9d and the fault detection information is xe2x80x9c0xe2x80x9d, it increments the fault release state continuation counter, and if the count value exceeds the set value, reports a fault release to the monitoring unit of maintenance personnel, monitoring device, etc. In this case too, the threshold value with respect to the count value of the fault detection state continuation counter of software counter unit 63 and the threshold value with respect to its fault release state continuation counter can each be set independently.
A fault occurrence in a transmission system is detected by fault detection units 51, and 61 of hardware composition, and a fault occurrence or fault release is reported from the software to the monitoring unit of maintenance personnel or a monitoring device, etc., and because it has the tendency of transmission device miniaturization and an increase in the number of circuits accommodated, there is a desire that the size of the hardware and software that detects and handles faults of many types should be made smaller.
In answer to such desires, the conventional example shown in FIG. 9 must have an up-down counter 52 for various types of faults, and therefore there is the problem that its hardware configuration becomes large. With the conventional example shown in FIG. 10, fault detection information and fault release information must be conveyed separately between the hardware and software, and in this case too, because it must be conveyed with the fault release information of the fault detection information according to the type of fault, there is the problem that it is difficult to reduce its size.
An object of this invention is to reduce its size and to make fault detection easy even if in multiplex transmission.
This and other objects are attained by a fault monitoring system that monitors faults and reports them to a monitoring unit including maintenance personnel, a monitoring device, etc. The fault monitoring system of the present invention comprises a fault detection unit that detects the occurrence of faults and the release of faults, and a fault history information generation logic unit that reports to a software counter unit, as fault history information of one-bit composition, presence of any changes, based on fault occurrence information or fault release information from the fault detection unit, the presence of any change for each reading timing, and the previous-time output information.
According to the present invention the fault monitoring system has a software counter unit that counts the consecutive number of times of the same fault history information from fault history information generation logic unit and reports the fault occurrences or fault releases to the monitoring unit upon reaching a set count value.
The fault monitoring system of the present invention further comprises a change detection unit that detects changes in the fault occurrence circuit number or other state information, and an output zero fixed control unit that forcibly resets the count value of the software counter unit that inputs the fault history information from fault history information generation logic unit when a change in the state information is detected by this change detection unit.
A fault reporting method of the present invention is a process in which it is decided whether there is any change for each reading timing of fault occurrence information or fault release information from fault detection units, fault history information of one-bit composition is formed, the consecutive number of times the same content of this history information is counted by a software counter unit, and when the count exceeds a set value, the fault occurrence or fault release is reported to the monitoring unit, which includes maintenance personnel, a monitoring device, etc.
In an embodiment, the fault reporting method is a process wherein state information that reports PDI-P code or other fault states or other states is extracted, the presence of any change in the extracted state information is detected, and when there is a change, the count value of the software counter unit that counts fault history information is forcibly reset, then a count operation is performed in accordance with the fault history information from the fault history information generation logic unit.